Highly selective PtCo bimetallic nanoparticles on silica for continuous production of hydrogen from aqueous phase reforming of xylose.

Hydrogen (H 2) is a promising energy vector for mitigating greenhouse gas emissions. Lignocellulosic biomass waste has been introduced as one of the abundant and carbon-neutral H 2 sources. Among those, xylose with its short carbon chain has emerged attractive, where H 2 can be catalytically released in an aqueous reactor. In this study, a composite catalyst system consisting of silica (SiO 2)-supported platinum (Pt)-cobalt (Co) bimetallic nanoparticles was developed for aqueous phase reforming of xylose conducted at 225 °C and 29.3 bar. The PtCo/SiO 2 catalyst showed a significantly higher H 2 production rate and selectivity than that of Pt/SiO 2 , whereas Co/SiO 2 shows no activity in H 2 production. The highest selectivity for useful liquid byproducts was obtained with PtCo/SiO 2. Moreover, CO 2 emissions throughout the reaction were reduced compared to those of monometallic Pt/SiO 2. The PtCo bimetallic nanocatalyst offers an inexpensive, sustainable, and durable solution with high chemical selectivity for scalable reforming of hard-to-ferment pentose sugars. [Display omitted] • Silica (SiO 2)-supported PtCo bimetallic nano-catalyst was tested for APR of xylose. • PtCo/SiO 2 demonstrated higher H 2 selectivity than monometallic Pt/SiO 2 and Co/SiO 2. • Co/SiO 2 showed no catalytic activity for the APR of xylose. • PtCo catalyst produced ethylene glycol, resulting in a higher H 2 production rate. • DFT calculations confirmed that the surface layer of Co atoms enhances the activity. [ABSTRACT FROM AUTHOR]